In moving paper XY recorders, a sheet of material, typically having a grid imprinted thereon, is moved in an X direction in accordance with one variable, such as time, and a stylus is moved across the material in the orthogonal Y direction in accordance with the other variable. Alignment of the grid with the XY axes of the recorder is essential if accurate readings of the plots are to be made. One way to do this is to align the grid with perforations along the edge of the material and move it with a sprocket wheel. Whereas this works in a satisfactory manner, it requires more expensive special paper that is not generally available. Another way of aligning the material is to provide a paper guide bar that is parallel to the X axis along which the paper moves, a stop that is parallel to the Y axis, and a continuously driven rubber friction roller oriented so as to drive the paper into the corner formed by the guide bar and the stop. Means are provided for sensing when the paper has settled into the corner, raising the stop, and causing drive rollers to engage the paper and move it forward into the machine. This approach requires a number of separate rather cumbersome mechanisms and, if the paper is very thin, as much grid paper is, it may buckle when it strikes the guide bar or the stop so that it will become misaligned when they are removed. Furthermore, the friction roller can only drive the paper into the corner so that it cannot compensate for any side force exerted by the operator or obstruction that would cause it to be too close to the guide bar.